Pressure release controls in hydraulic driving and stopping mechanisms



Dec. 13, 1966 J. R. IOANNILLI 3,

PRESSURE RELEASE CONTROLS IN HYDRAULIC DRIVING AND STOPPING MECHANISMS Filed June 24, 1964 5 Sheets-Sheet 1 J. R. lOANNlLLI Dec. 13, 1966 PRESSURE RELEASE CONTROLS IN HYDRAULIC DRIVING AND STOPPING MECHANISMS 5 Sheets-Sheet 2 Filed June 24, 1964 Dec. 13, 1966 J. R. lOANNlLLl PRESSURE RELEASE CONTROLS IN HYDRAULIC DRIVING AND STOPPING MECHANISMS 5 Sheets-Sheet 3 Filed June 24, 1964 3,291,083 PRESSURE RELEASE CONTROLS IN HYDRAULIC DRIVING AND STOPPING MECHANISMS Joseph R. Ioannilli, Beverly, Mass, assignor to United Shoe Machinery Corporation, Flemington, N.J., a corporation of New Jersey Filed June 24, 1964, Ser. No. 377,618 4 Claims. (Cl. 112-219) This invention relates to hydraulic driving and stopping mechanisms for lockstitch, shoe outsole sewing machines and, more particularly, to improvements in pressure release control for such driving and stopping mechanisms as those disclosed in an application for United States letters Patent Serial No. 208,847, filed July 10, 1962 in the names of Copithorne et al., including the present inventor, now U.S. Patent No. 3,142,278.

In the driving and stopping mechanisms of the application above identified a hydraulic driving motor is mechanically coupled to a main sewing shaft of a shoe outsole sewing machine, and a pump is connected to the inlet side of the motor for rotating the sewing shaft. To bring the sewing shaft to rest a flow restricting circuit is connected to the outlet side of the motor in a manner to apply an abrupt braking force to the sewing shaft. After the sewing shaft has been slowed down by the braking force and brought to rest the hydraulic load on the pump is released from back pressure by opening a vent valve between the pump and the motor. It is essential that the pressure be retained in the pressure conduit until rotation of the sewing shaft has been reduced to a slow speed and has reached a fixed stopping position. Accordingly, the vent valve is actuated by the use of an electrically actuated time delay relay connected to a solenoid in the valve, the time delay relay providing ample delay to enable the sewing shaft to be brought to rest.

A disadvantage appears in the use of a time delay relay in the machine of the prior application, because the means for initiating the time of operation of the relay is controlled automatically by movement of a positive stop or dog engaged by a shoulder on a cam secured to the main sewing shaft of the machine. The positive stop has imparted to it by an enlargement on the cam a movement before the machine comes to rest for performing several auxiliary operations, such as raising the presser foot from clamping engagement with the work and releasing the tension on the sewing thread, before the vent valve is actuated so that a completed shoe may be withdrawn from the machine without the necessity for unclamping it or severing the thread manually. In the prior machine it is occasionally desirable to readjust the movement imparted to the stop by the shouldered cam and such readjustment may interfere with proper initiation of the time period produced by the time delay relay. Also, if the amount of presser foot unclamping movement is increased in stopping the machine there is a possibility that the vent valve may be closed and the sewing shaft may start its rotation at the beginning of a new seam in the proper sequence, before the presser foot is able to re-engage the work, the time delay relay being ineffective, at this time. For this reason, a new shoe being operated upon may be disnited States Patent "ice placed from proper sewing position by the action of the stitch forming devices, so that initial sewing operations will not be performed with reliability.

In view of the difficulties noted it is an object of the present invention to provide a machine for performing operations, the operation performing devices in which are actuated by a main shaft driven by hydraulic driving and stopping mechanisms, including a positive stop for bringing the machine to rest in a predetermined position and also for controlling the sequence of auxiliary operations, in which machine the auxiliary operations may be adjusted readily without requiring the use of a time delay relay and without otherwise affecting the reliability with which the sewing operations are performed. In other respects a more general purpose of the invention is to facilitate adjusting hydraulic driving and stopping mechanisms for rotating a main shaft of a machine and for performing auxiliary operations incidental to the completion of the main operations.

For the purposes outlined a machine of the type referred to is provided with a cam on its main actuating shaft and a follower separate from a positive stop of the nature indicated above, to free the stop from any complication in adjustments of auxiliary operations performed after the machine has been brought to rest by a hydraulic stopping mechanism.

These and other features of the invention, as hereinafter described and claimed will become more readily apparent to those skilled in the art from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary sectional view, looking from the right side of a shoe outsole sewing machine embodying the features of the present invention;

FIG. 2 is a detail perspective view illustrating in sim-. plified form, electrically controlled hydraulic driving and stopping mechanisms for the machine of FIG. 1, taken from the right front while the machine is in stopped position;

FIG. 3 is a fragmentary rear view of a portion of the stopping mechanism;

FIG. 4 is a perspective detail view of connections for operating a pressure dump switch employed in the machine, parts having been displaced in order to illustrate better the features of construction; and

FIG. 5 is a further perspective detail view, illustrating interlock connections for controlling a positive stop for bringing the machine to rest in a predetermined position.

The sewing machine illustrated in the drawings is a curved hook needle lockstitch machine having hydraulic driving and stopping mechanisms for imparting rotation to and for stopping the rotation of a main sewing shaft at a predetermined position of rest within a single cycle of the machine, the final stopping position being determined by a positive mechanical stop in the form of a stopping dog, as disclosed in a prior application for United States Letters Patent Serial No. 261,342, filed February 27, 1963 in the names of Akerley and the present inventor and in the application above identified.

Referring to FIG. 2 0f the drawings, the illustrated machine has a main frame 10, in which are mounted a curved hook needle 12, a work support 14, a presser foot 16, a shuttle 18, and other stitch forming and work feed ing devices actuated by the main sewing shaft, indicated at 20. For driving the main sewing shaft the left end is mechanically connected to a hydraulic displacement unit in the form of a motor 22. The motor is connected by an inlet conduit 24 to a pump 26, which raises a supply of fluid contained in a sump 28 and applies pressure to it as it enters the conduit 24.

To regulate the speed of rotation of the sewing shaft the pressure conduit 24 has a by-pass running through a variable pressure control valve 30 connected for actuation by a rod 32 to a treadle 34 conveniently disposed for actuation by an operator for the machine. As the treadle 34 is depressed against the force of an extension spring 36 connected to it, the pressure control valve is closed off to cause rotation of the sewing shaft in a manner more fully disclosed in the Copithorne et al. application. Upon release of the treadle 34 the sewing shaft 20 is brought to rest by first retarding it from its maximum speed of operation to a fixed low speed and then by bringing it to a stopped position through the engagement of a positive stop or dog with a shoulder 38 on a stopping cam 40 (see FIG. 1) keyed to the main sewing shaft 20. As soon as the shoulder 38 engages the positive stop all pressure is released from the conduit 24, so that the pump 26 runs idly without the expenditure of unnecessary power and driving torque is discontinued on the main shaft.

For retarding rotation of the main shaft the outlet of the motor 22 is connected with an outlet conduit 42 (FIG. 2) provided with a retarding orifice 44, forming a flow restricting circuit, the action of which circuit quickly brings the speed of rotation in the sewing shaft to approximately 200 r.p.m. Thereafter, the positive stop moves into the path of movement of the shoulder 38 onv the stopping cam bringing the shaft to rest. The positive stop comprises a lever 46 carrying a roll 48 (FIG. 1) which engages the cam 40 and is movable into and out of the path of the cam.

The cam 40, as the shaft 20 is rotating in the direction of the arrow in FIG. 1 at low speed just before being brought to rest, engages the roll 48, moving the positive stop lever radially away from the shaft to perform the necessar auxiliary operations at the end of each seam. The stop lever 46 is pivoted diametrically on a hub of an auxiliary operation performing lever 50 rotatable on a shaft 51, so that the roll 48 may move along the sewing shaft into and out of the path of the cam 40, the stop lever being pressed yieldingly in a direction axially of the sewing shaft into the path of the cam by a tension spring 52 (see FIGS. 4 and connected between an arm of the stopping dog and a portion of the machine frame. When the cam 40 first engages the roll 48 an enlargement 49 (FIG. 1) on the cam moves the roll outwardly, imparting motion to the auxiliary operation performing lever 50 through an adjustable link 53 to an upstanding arm 54 pinned on a shaft 56 rotatable in the frame of the machine. A downwardly extending arm 55 fixed to the shaft 56 is pivotally connected to an inclined rod 58 acting when moved to the left in FIG. 1 to open thread locks and to release all tension on the thread, so that a shoe may be disengaged from the machine without severing the thread.

To raise the presser foot 16 from engagement with a shoe, so that it may readily be removed at the end of a seam from the machine, the upper end of the arm 54, as it is actuated by the stopping dog, is pressed rearwardly against the upper end of an arm 60 fixed to a shaft 62 rotatably mounted in the machine frame, said shaft also having fixed to it a downwardly extending arm 64. The arm 64 is connected by a link 66 to presser foot lifting mechanism, the link 66 corresponding to that identified by a numeral 300, as disclosed in United States Letters Patent No. 2,271,611, granted February 3, 1942 upon application of Fred Ashworth et al.

In the machine of the Copithorne et al. application it is occasionally necessary to adjust the link corresponding to the link 53 in order to increase or decrease the amount of raising movement imparted to the presser foot at the end of a seam. In the Copithorne et al. machine the auxiliary operation performing lever also acts when the machine is brought to rest to release all pressure from the hydraulic system, so that unnecessary expenditure of power will be avoided. For this purpose the pressure conduit 24 is vented through a valve corresponding to a valve 68 in the machine of the present invention.

Whenever an adjustment is made in the presser foot lifting action of the auxiliary operation performing lever in the prior machine, the time sequence at which the pressure conduit is vented at the end of a seam also may be disturbed. For this reason the machine may not accurately be brought to rest uniformly, or in starting the machine the presser foot may not clamp the work securely before the sewing shaft starts its rotation. As a result, a shoe or other work presented to the machine may be ejected by the action of the stitch forming devices, thus subjecting the work to possible damage or parts of the machine to breakage. To avoid these difliculties the auxiliary operation performing lever 50 is no longer utilized to cause the pressure conduit to be vented.

Instead of utilizing the auxiliary operation performing lever 50 to release fluid from the pressure conduit leading to the hydraulic motor, pressure venting means comprising an additional lever separate from the stopping lever 46 is actuated directly by the sewing shaft for this purpose, so that in accordance with the present invention adjustment of the auxiliary operation performing lever may be accomplished without affecting in any way the hydraulic mechanisms. The additional lever is indicated at 70 and has an upstanding arm arranged generally in parallel relation to the stopping lever 46. For actuating the lever 70 it has an upstanding arm provided with a rounded projection arranged to be engaged by a second cam 72 secured to the sewing shaft. The cam 72 is so shaped that it moves the upstanding arm of the lever 70 outwardly in a radial direction away from the sewing shaft at the same time the stopping lever 46 comes into engagement with the shoulder 38 on the stopping cam but continues the movement beyond the time of outward movement in the stopping lever.

The additional lever 70 also is mounted for movement into and out of the path of the cam 72 about a pair of radial pins 74 carried by a hub of an arm 76 rotatably mounted on the shaft 51 which also supports the auxiliary operation performing lever 50. The lower end of the arm 76 has threaded into it a set screw 78 disposed in alinement with a spring pressed plunger 80 slidingly mounted in a housing 82 for a vent valve actuating switch. To enclose the switch the housing has secured to it a cover 84.

To move the additional cam lever 70 into and out of the path of the cam 72, the lever 70 has a slotted finger at its upper end, through which passes a shoulder screw 86 threaded into a lateral projection of the stopping lever 46 to form a loose sliding connection between them. The curvatures of the cams 40 and 72 are nearly parallel except for the shoulder 38 on the stopping cam and the enlargement on the cam 72, which actuates the lever 70, this enlargement extending nearly to the stopping shoulder on the stopping cam. Because of the similar construction in the cams it is possible for the stopping lever 46 and the additional lever 70 to be moved together into and out of the paths of their respective cams, although they are capable of independent radial movement by those cams. For this purpose the screw 86 projects from the stop lever 46 a suitable distance. Whenever the stop lever 46 is moved along the shaft, however, the additional lever 70 tends to move in a corresponding manner.

As in the machine disclosed in the Akerley et al. application, the stop lever 46 is locked out of the path of the cam 40 until the stop shoulder 38 is a major fraction of a complete rotation away from the stop lever, so that ample opportunity is given for reducing the speed of the sewing shaft to a point where there is no possibility of damage to the parts when the shoulder does engage the stop lever 70. Locking the stop lever 46 also prevents the additional lever 70 from entering the path of its cam 72 during the same time.

The stop lever locking means comprises a releasable blocking arm 88 (FIG. 5) arranged for engagement with the auxiliary operation performing lever 50 until such time as it is safe to bring the stopping dog into the path of the cam 40. The blocking arm has a finger projecting into the path of the shoulder on the cam 40 and is arranged to be released by the shoulder, so that the stop lever may move into the path of the cam 40 just after the shoulder has passed beneath the blocking arm.

As shown in FIG. 1 the machine parts are shown after the sewing shaft 20 has been brought to rest and a pressure venting switch has been opened. Opening the venting switch causes the pressure to be vented through the valve 68 into the sump 28, so that no further power is absorbed by maintaining pressure in the conduit 24.

The pressure venting switch comprises a movable switch arm 90 pivoted for rotation about a screw 92 within the housing 82 and arranged to be engaged by the plunger 80. Before the machine comes to rest with the shoulder 38 engaging the stopping roll 48 the cam 72 moves the upper arm of the lever 70 outwardly to its furthest position and the set screw 78 engages the plunger 80 to disengage a movable contact on the arm 90 from a stationary contact 93 in the housing, opening a circuit to the venting valve 68. The switch contacts are held disengaged until the machine is restarted.

The parts then remain in the positions illustrated in FIG. 1 until the machine is restarted by depressing the treadle 34. Upon depressing the treadle both the stop lever 46 and the lever 70 are moved out of the paths of their respective cams. Force is then applied to both the stop lever 46 and the lever 70 to swing their upper ends toward the sewing shaft 20, thereby disengaging the set screw 78 from the plunger 80.

To apply force from the treadle 34 to the stop lever 46 the treadle rod 32 is connected to a cam lever 94 rotatable on the shaft 62, A downwardly extending arm of the lever 94 engages a roll 95 on a lever 96 fulcrumed on a shaft 97 in the machine frame and the lever 96 contacts the underside of the stop lever to move it out of the path of its cam 40.

To cause the contact on the movable switch arm 90 to be re-engaged with the stationary contact 93 the housing 82 has slidingly mounted in it at the opposite side from the plunger 80 a second spring pressed plunger 98 disposed in alinement with a set screw 99 carried by a downwardly extending arm of the auxiliary operation performing lever 50. In moving the upper end of the stop lever 46 inwardly toward the sewing shaft, the plunger 98 is engaged with the set screw 99 to move the contact on the switch arm 90 into engagement with the contact 93, a toggle spring 100 acting to hold the contacts in engagement. Also, the spring 108 holds the contacts disengaged after the switch arm 90 has been positively actuated by the plunger 80, thus avoiding any possibility of closing the vent valve 68 until the work is securely clamped by the 'presser foot.

To assist in moving the set screw 78 away from the plunger 80 when the stop dog and the lever 70 are moved out of the paths of their respective cams the arm 76 has projecting from one side of it a pin 102, between which and a pin 104 on the machine frame, there is stretched a tension spring 106. In starting operations on a new shoe the spring 106 rotates the arms 76 in a counterclockwise direction, both the levers 70 and 46 being moved inwardly toward the sewing shaft 28. Inward movement of the stop lever 46 causes the downwardly extending arm of the auxiliary operation performing lever 50 to be moved correspondingly and the switch 90 to be 6 actuated to close the circuit for the release valve 68. Pressure is then immediately restored to the inlet conduit 24 and the machine started.

The nature and scope of the invention having been indicated and a particular embodiment having been described, what is claimed is:

1. A machine for performing an operation having operation penforming devices, a main shaft for actuating the operation performing devices, and hydraulic driving and stopping mechanisms for rotating the main shaft, including a displacement unit mechanically connected to the main shaft, a pump, a pressure conduit connected between the displacement unit and the pump, a flow restricting circuit hydraulically connected to the displacement unit to retard rotation of the main shaft and a positive stop for bringing the machine to rest in a predetermined position after the flow restricting circuit retards rotation of the main shaft, in combination with pressure venting means actuated by the main shaft separately from the positive stop to release the pressure in the pressure conduit as the main shaft is brought to rest by the positive stop.

2. A machine for performing an operation having operating performing devices, a main shaft for actuating the operation performing devices, and hydraulic driving and stopping mechanisms for rotating the main shaft, including a displacement unit mechanically connected to the main shaft, a pump, a pressure conduit connected between the displacement unit and the pump, a flow restricting circuit hydraulically connected to the displacement unit to retard rotation of the main shaft and a positive stop for bringing the machine to rest in a predetermined position after the flow restricting circuit retards rotation of the main shaft, in combination with a cam having a shoulder secured to the main shaft, against which shoulder the positive stop acts in bringing the machine rest, pressure ventin-g means for releasing the pressure in the pressure conduit comprising a lever separate from the positive stop and a second cam on the main shaft for actuating the separate lever.

3. A shoe sewing machine having stitch-forming devices, a main sewing shaft for actuating the stitch-formin-g devices and hydraulic driving and stopping mechanisms for rotating the sewing shaft, including a displacement unit mechanically connected to the sewing shaft, a pump, a pressure conduit connected between the displacement unit and the pump, a flow restricting circuit hydraulically connected to the displacement unit to retard rotation of the sewing shaft, a cam having a shoulder secured to the sewing shaft and a positive stop movable toward and from the path of the shoulder on the cam for bringing the machine to rest in a predetermined position after the flow restricting circuit retards rotation of the sewing shaft, in combination with pressure venting means for releasing the pressure in the pressure conduit, said venting means comprising a second cam on the sewing shaft and a lever separate from the positive stop arranged for movement toward and from the path of the second cam, and means for moving the positive stop and the pressure venting lever together toward and from their respective cams while being capable of independent movement by those cams.

4. A shoe sewing machine having stitch-forming devices, a main sewing shaft for actuating the stitch-forming devices and hydraulic driving and stopping mechanisms for rotating the sewing shaft, including a displacement unit mechanically connected to the sewing shaft, a pump, a pressure conduit connected between the displacement unit and the pump, a flow restricting circuit hydraulically connected to the displacement unit to retard rotation of the sewing shaft, a cam having a shoulder secured to the sewing shaft and a positive stop movable toward and from the path of the shoulder on the cam for bringing the machine to rest in a predetermined position after the flow restricting circuit retards rotation of the sewing shaft, in

3, 2 9 1, 0 s3 7 8 combination with pressure venting means for releasing the References Cited by the Examiner pressure in the pressure conduit, comprising a second cam on the sewing shaft and a lever separate from the positive UNITED STATES PATENTS stop arranged for movement toward and from the path of 2,271,611 2/1942, A h o th et a1, 112 38 the second cam, and a loose connection between the posi- 5 2,646,152 7/1953 Retz 192-149 five p the pressure venting lever, comprising a 3,142,278 7/1964 Copithorne et a1 112-219 slotted finger and a screw for moving the positive stop and the pressure venting lever together toward and from JORDAN FRANKLIN Primary Emmi-"en their respective cams while be1ng capable of independent movement by those cams. 10 H. H. HUNTER, Assistant Examiner. 

1. A MACHINE FOR PERFORMING AN OPERATION HAVING OPERATION PERFORMING DEVICES, A MAIN SHAFT FOR ACTUATING THE OPERATION PERFORMING DEVICES, AND HYDRAULIC DRIVING AND STOPPING MECHANISMS FOR ROTATING THE MAIN SHAFT, INCLUDING A DISPLACEMENT UNIT MECHANICALLY CONNECTED TO THE MAIN SHAFT, A PUMP, A PRESSURE CONDUIT CONNECTED BETWEEN THE DISPLACEMENT UNIT AND THE PUMP, A FLOW RESTRICTING CIRCUIT HYDRAULICALLY CONNECTED TO THE DISPLACEMENT UNIT TO RETARD ROTATION OF THE MAIN SHAFT AND A POSITIVE STOP FOR BRINGING THE MACHINE TO REST IN A PREDETERMINED POSITION AFTER THE FLOW RESTRICTING CIRCUIT RETARDS ROTATION OF THE MAIN SHAFT, IN COMBINATION WITH PRESSURE VENTING MEANS ACTUATED BY THE MAIN SHAFT SEPARATELY FROM THE POSITIVE STOP TO RELEASE THE PRESSURE IN THE PRESSURE CONDUIT AS THE MAIN SHAFT IS BROUGHT TO REST BY THE POSITIVE STOP. 